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37 Cards in this Set
- Front
- Back
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What is air pressure?
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The pressure exerted by the weight of air above.
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What is a mercury barometer?
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A mercury-filled glass tube in which the height of the mercury column is a measure of air pressure.
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What is a aneroid barometer?
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An instrument for measuring air pressure that consists of evacuated metal chambers that are very sensitive to variations in air pressure.
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What is a barograph?
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A recording barometer.
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What is wind?
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Air flowing horizontally with respect to Earth's surface.
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What is the ultimate energy source for most wind?
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solar radiation
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What are the 3 factors that affect wind?
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1. the pressure gradient force
2. the Coriolis effect 3. friction |
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What are isobars?
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A line drawn on a map connecting points of equal atmospheric pressure, usually corrected to sea level.
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What is pressure gradient?
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The amount of pressure change occurring over a give distance.
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What is Coriolis effect?
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The deflective force of Earth's rotation on all free-moving objects, including the atmosphere and oceans.
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What are geostrophic winds?
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A wind, usually above a height of 600 meters, that blows parallel to the isobars.
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What are jet streams?
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Swift high-altitude winds
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What are cyclones or lows?
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A low-pressure center characterized by a counterclockwise flow of air in the Northern Hemisphere.
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What are anticyclones or highs?
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A high-pressure center characterized by a clockwise flow of air in the Northern Hemisphere.
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What is convergence?
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The condition that exists when the distribution of winds within a given area results in a net horizontal inflow of air into the area. favorable for cloud formation and precipitation
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What is divergence?
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The condition that exists when the distribution of winds within a given area results in a net horizontal outflow of air from the region. unfavorable for cloud formation and precipitation.
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What is pressure or barometric tendency?
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The nature of the change in atmospheric pressure over the past several hours.
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What is the equatorial low?
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A belt of low pressure lying near the equator and between the subtropical highs.
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What is a the subtropic high?
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Not a continuous belt of high pressure but rather several semipermanent, anticyclonic centers characterized by subsidence and divergence located roughly between 25 and 35 degrees.
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What are trade winds?
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Two belts of winds in that blows almost constantly from easterly directions and are located on the equator ward sides of the subtropical highs.
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What are westerlies?
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The dominant west-to-east motion of the atmosphere that characterizes the regions on the poleward side of the subtropical highs.
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What are polar easterlies?
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In the global pattern of prevailing winds, winds that blow from the polar high toward the sub-polar low. not consistent like trade winds.
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What is the subpolar low?
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Low pressure located at about the latitudes of the Arctic and antarctic circles.
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What are polar fronts?
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The stormy frontal zone separating air masses of polar origin from air masses of tropical origin.
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What is the polar high?
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Anticyclones that are assumed to occupy the inner polar regions and are believed to be thermally induced (partially).
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What are monsoons?
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Seasonal reversal of wind direction associated w/ large continents, especially Asia. In winter=wind blows land to sea.
Summer=wind blows sea to land |
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What produces wind?
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Pressure differences that arise because of temperature differences that are caused by unequal heating of Earth's surface.
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What is a sea breeze?
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A local wind blowing from the sea during the afternoon in coastal areas.
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What is a land breeze?
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A local wind blowing from land toward the water during the night in coastal areas.
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What is a valley breeze?
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The daily upslope winds commonly encounter in a mountain valley.
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What is a mountain breeze?
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The nightly downslope winds commonly encountered in mountain valleys.
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What are chinooks?
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A wind blowing down the leeward side of a mountain and warming by compression.
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What is the Santa Ana?
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The name given a chinook wind in southern CA.
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How are winds labeled?
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By th direction from which they blow.
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What is a wind vane?
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An instrument used to determine wind direction.
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What are prevailing winds?
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A wind that consistently blows from one direction more than from any other.
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What is a cup anemometer?
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An instrument used to determine wind speed.
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